Method of uniting metals



Oct. 30, 1934. J. M. CQLLINS 1,978,415

METHOD OF UNITING METALS Filed Dec. 24, 1931 gwuento z Jam, /Y. @0015,

Oct. 30,1934. J, coLLlNs METHOD OF UNITING METALS Filed Dec. 24, 1951Jmntoc Patented Oct. 30, 1934 METHOD or um'rme METALS John M. Collins,Springfield, Mam, assignor to Moore Drop Forging Company, Springfield,Mass, a corporation of Massachusetts Application December 24, 1931,Serial No. 583,108

2 Claims.

The object of this invention is to provide a new method of unitingmetals, and particularly relates to an improvement or modification ofthe method described and claimed in an application for patcut by AlbertW. Morris filed Nov. 21, 1931, Serial The method described and claimedin said application for patent has particular reference to impregnatingthe surface of a ferrous article to a suitable depth with a metal oralloy having an ailinity for nitrogen. The specific way thisimpregnating is obtained in the method described in said application isby immersing the ferrous article while hot in a bath of molten metalhaving an affinity for nitrogen.

I have found that the broad method above described can be carried out bycoating the metal piece with a spray of molten metal having a relativelylower melting point than the metal piece, the metal piece being kept ata temperature above the melting point of the sprayed material during theoperation.

The specific method can be practiced by impregnating the surface of aferrous casting or forging by coating the same with a spray of moltenmetal or alloy having an affinity for nitrogen, the casting or forgingbeing kept at a temperature above that of the melting point of thesprayed material during the operation. Preferably the heat used inmaking the casting or forging is employed as far as possible to maintainthe piece to be treated at the temperature specified.

Many forms of apparatus can be devised for carrying out my improvedmethod, and one simple apparatus is illustrated in the accompanyingdrawing, in which:---

Fig. 1 is an end elevation of enough of an apparatus to illustrate howthe method may be practiced, and

Fig. 2 is a plan view thereof.

Referring to the drawing and in detail, A--A designate spraying nozzlessuch as are usually employed in hot spraying. These nozzles may bearranged on a screw B so that they may travel back and forth by rotatingthe screw alternately in different directions. C--C designate centers onwhich the forging or casting F to be treated can be held. One of thesecenters preferably is provided with flutes or grooves so that byrotating the same, the piece F is rotated so that its entire surface canbe sprayed.

If desired a number of gas jets can be arranged to maintain the piece Fat the desired temperature.

In operation, the piece F is taken as hot as possible after it has beenshaped by the forging or casting process, and placed on the centers androtated, and sprayed by the nozzles.

If the article is to be prepared for the nitriding process, the same ismade of iron or steel, or of any suitable ferrous alloy, and the sprayis formed of a molten metal having an aflinity for nitrogen. This moltenmetal usually is aluminum or some aluminum alloy, known in the 05 art assusceptible of hardening by being subjected to free nitrogen.

By spraying in this manner, there will be a considerable penetration ofthe spray into the surface of the article treated so that when the sameis nitrided a hard shell will be formed thereon.

The method can be practiced with other metals. For instance, a rustresisting compound may be sprayed on a hot piece or a babbltting alloyor bearing material may be sprayed on a hot shaft or journal. Thusthemethod may be applied to many different purposes.

Many other forms of apparatus may be devised by a skilled mechanic forpracticing my improved method without departing from the scope of theinvention as specified in the claims.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

l. The method of making a ferrous, cast or forged piece nitridable,which consists in taking the piece as hot as possible after casting orforging, and coating and impregnating the surface thereof with a sprayof a molten metal or alloy having an ailinity for nitrogen, thetemperature of the piece being above the melting point of the sprayedmaterial during the operation.

2. The method of making a ferrous, cast or forged piece nitridable,which consists in taking the piece as hot as possible after casting orforging, and coating and impregnating the surface thereof with a sprayof a molten aluminum or aluminum alloy, and maintaining the temperatureof the piece above the melting point of the sprayed material during theoperation.

JOHN M. COLLINS.

